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Part 021 – Physics Previous Year Questions

Q1. A solid needle placed horizontally on the surface of the water floats due to
(a) capillary action
(b) water pressure
(c) surface tension of water
(d) viscosity of water
Ans: (c) A solid needle placed horizontally on the surface of water floats due to surface tension of water.

Q2. When hot liquid is poured into a thick glass tumbler, it cracks because glass :

(a) is a bad conductor of heat so only inner surface expands
(b) has high temperature coefficient of expansion
(c) has a very low specific heat
(d) has low temperature coefficient of expansion
Ans: (a) When hot liquid is poured into a thick glass tumbler, it cracks because glass is a bad conductor of heat so only inner surface expands.

Q3. Hydro-electric power is a:

(a) non-renewable natural resource
(b) a mixture of renewable and non-renewable natural resource
(c) neither renewable nor non renewable resource
(d) renewable natural resource
Ans: (d) Hydro-electric power is a renewable natural resource.

Q4. The oil in the wick of an oil lamp rises up due to:

(a) capillary action
(b) low viscosity of oil
(c) gravitational force
(d) pressure difference
Ans: (a) The oil in the wick of an oil lamp rises up due to capillary action.

Q5. A drop of liquid assumes spherical shape because:

(a) Intermolecular forces are strong in liquids
(b) A sphere has the least surface area for a given volume
(c) A sphere has the largest surface area for a given volume
(d) Inter molecular forces are weak in liquids
Ans: (b) A drop of liquid assumes spherical shape because a sphere has the least surface area for a given volume.

Q6. If cream is removed from milk, its density

(a) Increases
(b) Decreases
(c) Remains the same
(d) May increase or decrease
Ans: (a) The density of pure fresh milk being on the average 1.032, while the density of fat globules is about 0.86. It follows that the removal of cream will increase the density, while the addition of water will decrease it.

Q7. Convex mirrors are used as a rear view mirror in motor cycles because

(a) it forms real image
(b) it forms erect (upright) image
(c) it forms smaller image as compared with object
(d) All of the above
Ans: (c) It is because image formed by an convex mirror is always virtual, erect and smaller than the object.

Q8. The wall of a dam is made thicker at the bottom than at the top because the pressure exerted by the water on the wall

(a) depends on the thickness of the wall
(b) increases with height of the wall
(c) increases with depth of the wall
(d) depends on the area of the wall
Ans: (c) Higher water pressure on the base of the dam needs greater strength to hold it back.

Q9. Full form of CFL used in place of electric bulbs is

(a) compact fluorescent lamp
(b) constantan filament lamp
(c) closed filament lamp
(d) closed fluorescent lamp
Ans: (a) A compact fluorescent lamp (CFL) is a fluorescent lamp designed to replace an incandescent lamp; some types fit into light fixtures formerly used for incandescent lamps.

Q10. Indicate the false statement about the resistance of a wire

(a) it depends on material of wire
(b) it is directly proportional to the length of wire
(c) it is directly proportional to the area of cross-section of wire
(d) resistance of metallic wire increases with increase in temperature
Ans: (c) The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it. The SI unit of resistance is ohm.

Q11. Which electromagnetic radiation is used for satellite communication ?

(a) Ultraviolet
(b) Infrared
(c) Microwave
(d) Millimeter wave
Ans: (c) Microwave electromagnetic radiation is used for satellite communication.

Q12. Solar cells work on the principle of

(a) photovoltaic effect
(b) photoelectric effect
(c) photoconductive effect
(d) photosynthesis
Ans: (a) Solar cells work on the principle of photovoltaic effect.

Q13. Materials for rain proof coats and tents owe their water proof properties to

(a) Surface tension
(b) Viscosity
(c) Specific gravity
(d) Elasticity
Ans: (a) Materials for rain proof coats and tents owe their water proof properties to Surface Tension. The surface of a liquid behaves like an elastic membrane and therefore, has a tendency to contract. This property of liquid is called Surface Tension.

Q14. X-rays region lies between

(a) Ultraviolet and visible region
(b) Visible and infra-red region
(c) Gamma-rays and ultraviolet region
(d) Short radio waves and long radio waves
Ans: (c) X-rays region lies between Gamma rays and ultraviolet region.

Q15. A star appears twinkling in the sky because of

(a) scattering of light by atmosphere
(b) reflection of light by atmosphere
(c) refraction of light by atmosphere
(d) diffraction of light by atmosphere
Ans: (c) A star appears twinkling in the sky because of refraction of light by atmosphere. Light bends when it passes obliquely from one medium to another. This is called refraction of light.

Q16. When two ice cubes are pressed together, they join to form one cube. Which one of the following helps to hold them together?

(a) Hydrogen bond formation
(b)Vander waals forces
(c) Covalent attraction
(d) Dipole interaction
Ans: (a) When two ice cubes are pressed together, they join to form one cube due to hydrogen bond.

Q17. Microphone is a device which transforms the

(a) sound signal into current signal
(b) current signal into sound signal
(c) sound signal into light signal
(d) light signal into sound signal
Ans: (a) Microphone is a device which transforms the sound signal into current signal.

Q18. Pressure Cooker cooks faster because

(a) boiling point decreases with rise of pressure
(b) it cooks the food at low pressure
(c) higher temperature is attained for cooking
(d) the material of the cooker is a good conductor
Ans: (c) In pressure cooker boiling point of water increases due to high pressure.

Q19. When a strong beam of light is passed through a colloidal solution, the light will

(a) be scattered
(b) pass unchanged
(c) be absorbed
(d) be reflected
Ans: (a) When a strong beam of light is passed through a colloidal solution, the light will be scattered.

Q20. The dynamo converts

(a)mechanical energy into electrical energy
(b) electrical energy into mechanical energy
(c) mechanical energy into magnetic energy
(d)magnetic energy into mechanical energy
Ans: (a) mechanical energy into electrical energy

Q21. It is easier for a man to swim in sea water, than in river water because

(a) the density of sea water is lesser than the density of river water
(b) the density of sea water is more than the density of river water
(c) the sea is-deeper than the river
(d) the sea is wider than the river
Ans: (b) the density of sea water is more than the density of river water

Q22. In the remote control of television, electromagnetic waves used are

(a) ultraviolet (b) microwave
(c) radiowave (d) infrared
Ans: (d) All electromagnetic waves used are infrared.

Q23. The waveform of a certain signal can be studied by

(a) Spectrometer
(b) Cathode ray oscilloscope
(c) p – n junction diode
(d) Sonometer
Ans: (d) A spectrometer is an istrument used to measure properties of light over a specific portion of the electromagnetic spectrum. Cathode ray oscilloscope is an electronic display device containing cathode-ray tube (CRT) that generates an electron beam that is used to produce visible patterns or graphs on a phosphorescent screen. A sonometer is an apparatus made of hollow box having two holes. A string is attached to it by which the transverse vibrations of strings can be studied.

Q24. A wire carrying current is

(a) positively charged
(b) negatively charged
(c) neutral
(d) charged with a type depending upon current strength
Ans: (c) A wire carrying current is neutral.

Q25. A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers.

(a) reflection
(b) refraction
(c) diffraction
(d) total internal reflection
Ans: (d) If the angle of incidence of light ray in the denser medium is greater than the critical angle of the concerned media pair, the light is not at all reflected in to the rarer medium but is totally reflected. This is known as ‘total internal reflection’.

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